NIST time and frequency radio stations :

Nelson, Glenn K.; Lombardi, Michael A.; Okayama, Dean T

doi:10.6028/nist.sp.250-67

Cited by 18 publications

(40 citation statements)

References 7 publications

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“…1), could be used with LWA1's TB modes to probe the ionosphere. WWV broadcasts the time at 2.5, 5, 10, 15, and 20 MHz, including a 5 ms pulse at the beginning of each UT second (Nelson et al, 2005) that can be used for ranging. The frequency overlap between LWA1 and WWV is thus at 10, 15, and 20 MHz.…”

Section: Lwa1 Wwv Fais and Meteor Trailsmentioning

confidence: 99%

A multi-platform investigation of midlatitude sporadic E and its ties to E–F coupling and meteor activity

Helmboldt

2016

Ann. Geophys.

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Abstract. This paper describes the results of a multiplatform observing campaign aimed at studying midlatitude sporadic E (E s ) and associated ionospheric phenomena. The assets used were the digisonde in Boulder, Colorado; the first station of the Long Wavelength Array, LWA1, in New Mexico; the transmitters of the radio station WWV in Colorado; and 61 continuously operating GPS receivers between LWA1 and WWV. The results show that southwestward-directed medium-scale traveling ionospheric disturbances (MSTIDs) were substantially more prevalent when E s was detected. The amplitudes of these correlate with a plasma frequency up to about 4.5 MHz. For f p 5 MHz, the MSTIDs become significantly weaker and basically vanish above ∼ 6.5 MHz. The prevalence of meteor trail reflections observed with LWA1 also correlates with f p up to about 4.5 MHz; above this limit, the relationship exhibits a significant turnover. The observed intensity of coherent backscatter from E s field-aligned irregularities (FAIs) also correlates with inferred plasma frequency. However, this trend continues to higher frequencies with a peak near 6 MHz, followed by a much more subtle turnover. The reflected power from E s structures observed with LWA1 is significantly more correlated on spatial scales between 10 and 40 km. The magnitude of this correlation increases with f p up to ∼ 6 MHz, above which it drops. These results are consistent with the following: (1) southwestwarddirected MSTIDs are produced via E-F coupling; (2) this coupling is stronger when the E s layer, seeded by meteor ablation, is more dense; (3) the coupling is substantially diminished for E s layers harboring extremely dense structures (f p 5 MHz).

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Section: Lwa1 Wwv Fais and Meteor Trailsmentioning

confidence: 99%

A multi-platform investigation of midlatitude sporadic E and its ties to E–F coupling and meteor activity

Helmboldt

2016

Ann. Geophys.

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“…Because UTC(NIST) is a close real-time approximation of UTC, it can also be utilized as an official time source for financial exchanges throughout the world. NIST distributes UTC(NIST) to the general public through a variety of services that operate over various mediums including WWV, WWVH, and WWVB, which broadcast time signals via high frequency (HF) and low frequency (LF) radio signals [16,32]; by the Automated Computer Time Service (ACTS), which broadcasts time codes via ordinary telephone lines [33]; and by the Internet Time Service (ITS), which broadcasts billions (10 9 ) of time codes per day via the public Internet [17]. However, due to uncompensated propagation delays, each of these services delivers time to the user that is far less accurate than the time kept at NIST.…”

Section: Coordinated Universal Time (Utc) and Utc(nist)mentioning

confidence: 99%

Accurate, Traceable, and Verifiable Time Synchronization for World Financial Markets

Lombardi

Novick

Neville-Neil³

et al. 2016

J. RES. NATL. INST. STAN.

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The National Institute of Standards and Technology (NIST), through a collaboration with Perseus, a global provider of telecommunication services, is providing accurate, traceable, and verifiable time synchronization to stock exchanges in the United States, Europe, and Asia. The paper describes why accurate time is necessary for fair and equitable financial markets and summarizes current and proposed future synchronization requirements in the financial sector. We discuss reference time sources and provide a technical overview of how NIST transfers time to data center hosted stock exchange. We also discuss how Perseus distributes NIST time to financial market customers and describes how the time is verified. Measurement data are presented, along with a discussion of measurement uncertainty.

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“…Letter circulars were guides used to distribute technical information to users on various subjects related to the NBS's activities, while broadcasting allowed the NBS to reach an even wider audience. Broadcasts of ionospheric conditions and warnings of expected radio propagation disturbances across the North Atlantic began in June 1937 over station WWV in Maryland and were supplemented in 1948 with the creation of station WWVH in Hawaii which provided coverage and forecasts of conditions in the North Pacific and Alaska [ Snyder and Bragaw , ; Nelson et al ., ]. These early products and services provided valuable information to radio users and operators.…”

Section: Understanding the Ionospherementioning

confidence: 99%

An abridged history of federal involvement in space weather forecasting

Caldwell¹,

McCarron²,

Jonas³

2017

Space Weather

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Public awareness of space weather and its adverse effects on critical infrastructure systems, services, and technologies (e.g., the electric grid, telecommunications, and satellites) has grown through recent media coverage and scientific research. However, federal interest and involvement in space weather dates back to the decades between World War I and World War II when the National Bureau of Standards led efforts to observe, forecast, and provide warnings of space weather events that could interfere with high‐frequency radio transmissions. The efforts to observe and predict space weather continued through the 1960s during the rise of the Cold War and into the present with U.S. government efforts to prepare the nation for space weather events. This paper provides a brief overview of the history of federal involvement in space weather forecasting from World War II, through the Apollo Program, and into the present.

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NIST time and frequency radio stations :

Cited by 18 publications

References 7 publications

A multi-platform investigation of midlatitude sporadic <i>E</i> and its ties to <i>E</i>–<i>F</i> coupling and meteor activity

A multi-platform investigation of midlatitude sporadic <i>E</i> and its ties to <i>E</i>–<i>F</i> coupling and meteor activity

Accurate, Traceable, and Verifiable Time Synchronization for World Financial Markets

An abridged history of federal involvement in space weather forecasting

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NIST time and frequency radio stations :

Cited by 18 publications

References 7 publications

A multi-platform investigation of midlatitude sporadic &lt;i&gt;E&lt;/i&gt; and its ties to &lt;i&gt;E&lt;/i&gt;–&lt;i&gt;F&lt;/i&gt; coupling and meteor activity

A multi-platform investigation of midlatitude sporadic &lt;i&gt;E&lt;/i&gt; and its ties to &lt;i&gt;E&lt;/i&gt;–&lt;i&gt;F&lt;/i&gt; coupling and meteor activity

Accurate, Traceable, and Verifiable Time Synchronization for World Financial Markets

An abridged history of federal involvement in space weather forecasting

Contact Info

Product

Resources

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A multi-platform investigation of midlatitude sporadic <i>E</i> and its ties to <i>E</i>–<i>F</i> coupling and meteor activity

A multi-platform investigation of midlatitude sporadic <i>E</i> and its ties to <i>E</i>–<i>F</i> coupling and meteor activity